I'd actually support the hell out of it (as long as it's not incest/paedophilia/abusive as some already mentioned) as I myself am sad that I can only put like 10% of my own ships into canon. I think the only thing I'd ask of people is to be respectful to gender identities and sexual orientations when it comes to explicitly canon trans or gay/lesbian characters. But since most characters are very free for interpretation and/or fall onto the bi/pan spectrum canonically, I'd say go wild!
Definitely would be curious what kind of crack ships people came up with and not gonna lie, I'd read the filthiest crack smut fic because seriously, someone loves my characters enough to open up a word document, that's such an amazing thought and an Accomplishment for me.
(I know that my Trusted Person already ships some characters but they also kinda get teased in the canon anyway.)